This present application relates to cooling hot gas path components in combustion or gas turbine engines. More specifically, but not by way of limitation, the present application relates to a plenum configuration for delivering coolant to turbine stator blades.
Generally, combustion or gas turbine engines (hereinafter “gas turbines”) include compressor and turbine sections in which rows of blades are axially stacked in stages. Each stage typically includes a row of circumferentially-spaced stator blades, which are fixed, and a row of rotor blades, which rotate about a central turbine axis or shaft. In operation, generally, the compressor rotor blades are rotated about the shaft, and, acting in concert with the stator blades, compress a flow of air. This supply of compressed air then is used within a combustor to combust a supply of fuel. The resulting flow of hot expanding combustion gases, which is often referred to as working fluid, is then expanded through the turbine section of the engine. Within the turbine, the working fluid is redirected by the stator blades onto the rotor blades so to power rotation. The rotor blades are connected to a central shaft such that the rotation of the rotor blades rotates the shaft. In this manner, the energy contained in the fuel is converted into the mechanical energy of the rotating shaft, which, for example, may be used to rotate the rotor blades of the compressor, so to produce the supply of compressed air needed for combustion, as well as, rotate the coils of a generator so to generate electrical power. During operation, because of the high temperatures, velocity of the working fluid, and rotational velocity of the engine, many of the components within the hot gas path become highly stressed by the resulting mechanical and thermal loads.
Many industrial applications, such as those involving power generation and aviation, still rely heavily on gas turbines, and because of this, the engineering of more efficient engines remains an ongoing and important objective. As will be appreciated, even incremental advances in machine performance, efficiency, or cost-effectiveness are meaningful in the highly competitive markets that have evolved around this technology. While there are several known strategies for improving the efficiency of gas turbines, such as, for example, increasing the size of the engine, firing temperatures, or rotational velocities, each of these generally places additional strain on hot-gas path components. As a result, there remains a need for improved apparatus, methods or systems that alleviate such operational stresses or, alternatively, that enhance the durability of such components so they may better withstand them.
As will be appreciated, this need is particularly evident in regard to turbine stator blades, where marketplace competitiveness is exceedingly high and the many design considerations are complex and often competing. As such, designs for more effectively delivering coolant to stator blades—such as those presented herein in relation to a novel plenum configuration—which also succeed in balancing the many other applicable design considerations represent technological advances having considerable economic value.